Question: $\overline{AC}$ is $3$ units long $\overline{BC}$ is $9$ units long $\overline{AB}$ is $3\sqrt{10}$ units long What is $\cos(\angle BAC)$ ? $A$ $C$ $B$ $3$ $9$ $3\sqrt{10}$
Answer: SOH CAH TOA os = djacent over ypotenuse adjacent $= \overline{AC} = 3$ hypotenuse $= \overline{AB} = 3\sqrt{10}$ $\cos(\angle BAC )=\frac{3}{3\sqrt{10}}$ $=\dfrac{ \sqrt{10}}{10}$